Interstate 66

Interstate 66
Custis Memorial Parkway
Route information
Length:	76.38 mi (122.92 km)
Major junctions
West end:	I‑81 in Middletown, VA
	US 340 / US 522 near Front Royal, VA US 17 near Warrenton, VA US 15 in Haymarket, VA SR 234 near Manassas, VA US 50 near Fairfax, VA I‑495 in Dunn Loring, VA SR 267 near Falls Church, VA
East end:	US 29 in Washington, DC
Location
States:	Virginia, District of Columbia
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Virginia Routes Interstate U.S. Primary Secondary Byways History Streets and Highways of Washington, D.C. Interstate U.S D.C. State-Named Streets ← SR 65 VA SR 67 → ← US 50 DC I‑95 →

Interstate 266
Location:	Arlington, Virginia–Washington DC
Existed:	1960s–1972

Interstate 66 (I-66) is an Interstate Highway in the eastern United States. As indicated by its even route number, it runs in an east–west direction. Its current western terminus is in Middletown, Virginia, at an interchange with Interstate 81; its eastern terminus is in Washington, D.C., at an interchange with U.S. Route 29. Because of its terminus in the Shenandoah Valley, the highway was once called the "Shenandoah Freeway." Much of the route parallels U.S. Route 29 or Virginia State Route 55. Interstate 66 has no physical or historical connection to the famous U.S. Route 66 which is in a different region of the United States.

The E Street Expressway is a spur from Interstate 66 into the Foggy Bottom neighborhood of Washington, D.C.

Because I-66 is the only Interstate Highway running west from Washington, D.C., into Northern Virginia, traffic on the road is often extremely heavy. For decades, there has been talk of widening I-66 from 2 to 3 lanes each way inside the Capital Beltway (Interstate 495) through Arlington, Virginia, although many Arlington residents are adamantly opposed to this plan.

In 2005, the Virginia Department of Transportation (VDOT) studied the prospect of implementing a one-lane-plus-shoulder extension on westbound I-66 within the Beltway (in an attempt to reduce congestion for people commuting away from D.C.).

...
Wikipedia